Autism Spectrum Disorder

November 9, 2009

Language development an important key to unlocking the mystery of Autism

Suzanne Curtin and her team are hoping to uncover how children, who are at high risk of developing Autism, process speech and other sounds.
Photo: Ken Bendiktsen

Suzanne Curtin, a psycholinguist in the Faculty of Social Sciences, is studying the developmental language trajectory of children with Autism Spectrum Disorder (ASD). Since ASD affects social communication development, learning how those infants at risk for developing ASD attend to information in their environment and process that information to learn language may give researchers insight into the disorder and result in better early identification and intervention.

By following the younger siblings of children with Autism from just four months of age, she and her team are hoping to uncover how children, who are at high risk of developing Autism, process speech and other sounds.

“We are looking for early patterns among these babies that deviate from other infants of the same age,” says Curtin. “Babies have initial preferences in what sounds they like to hear. When people talk to babies, they tend to change their voices to create a higher pitch and more vocal intonation. Babies really like this, but older children diagnosed with autism don’t show a preference for it compared to speech that is more adult-directed and monotone. Of particular importance to us is finding out if babies at risk for ASD like to listen to human speech more than to non-vocal sounds.”

Curtin uses a speech synthesizer to extract sound properties from vocal speech and re-create the sound without the human voice qualities. Then she plays the sounds, both containing and not containing the human voice quality, for a baby to hear and monitors the baby’s response. For example, a deceleration of the heart rate indicates that a baby is mentally engaged in something. Another way she tracks their response is to show an interesting visual display on a screen that is connected to the sounds. She then monitors how long the baby watches the screen as an indication of whether they’re paying attention to and interested in the sound.

Engagement with speech sounds is critical to developing language and perhaps social communication. It also enables babies and children respond when parents teach them a task and perhaps to develop joint attention – sharing an experience through communication with another person.

“If a particular baby doesn’t listen to speech, isn’t engaged in social communication, is having adverse responses to things in their environment, we begin to see a pattern. It will tell us if these are the right variables to be looking at and can result in early identification of children who may develop Autism.”

Curtin says ASD is usually diagnosed between a child’s second and third birthday. She and co-researcher, Shirley Leew, a registered speech-language pathologist and pediatric rehabilitation clinical research scientist with Alberta Health Services, test the younger siblings of children with ASD at four, six, eight, twelve and eighteen months of age and compare their results to a matched control group of siblings of children without ASD. It is their hope that the study will help researchers to better understand how children with autism develop social communication skills and language or how their development of social communication and language may be delayed.